The strain fatigue property of the welding fittings of Zr-Sn-Nb alloy plates was investigated both at room temperature and 375 ℃, and also we compared that with the smoothed samples. The results showed that the fatigue life of welding samples was less than half of that of the smoothed samples. The fatigue property of longitudinal samples was obviously better than that of transverse samples both at room temperature and 375 ℃. The cycle plastic strain range and the fatigue life followed the Coffin-Manson relation. The cycle- deformation property of the welding fittings differed at different temperature and strains. The microstructure and the fatigue crack were also investigated.